April 20, 1958
COMMUNICATIONS TO THE EDITOR
2023
creted unaltered. Aminoacetonitrile, 2,2'-imino- b y hydrogen reduction of the U308 to UOZ,nor by diacetonitrile and y-aminobutyronitrile failed to hydrogen firing of mixtures produced by evaporagive rise to cyanoacetic acid. It appears that in tion of various solutions containing U and Pu. the metabolism of BAPN and certain other ali- Coprecipitation of the U and Pu as peroxide was phatic nitriles by the rat the organic cyano group is also tried and was not successful. After the samples were esamined by X-ray diflargely unaffected and that deamination and/or oxidation occur a t the other end of the molecule. fraction, a radiochemical Pu assay was done to Results to date tend to indicate that aliphatic check the composition. The Pu assay agreed with nitriles are metabolized in the animal body to form the compositions as made in each case. X-Ray powder patterns were taken in a 114.6 w-carboxynitriles which then undergo cleavage as proposed for the fatty acids5 The color reaction mm. diameter powder camera using filtered copper with diazotized sulfanilic acid affords a very sensi- K-radiation. (Wave lengths, a1 = 1.54051, a2 = tive method for detecting cyanoacetic acid and may 1.54433, mean a = 1.5418 A.) The lattice parambe useful for studying the metabolism of other or- eter was determined in most cases by graphical ganic cyano derivatives. A detoxication product extrapolation of the values found for the high-angle of inorganic cyanide, 2-imino-4-thiazolidine car- lines on each pattern. Results are presented in boxylic acid,6 gives a somewhat similar color with Table I. The error limits on the compositions are this reagent but is easily distinguished from cyano- estimated, those on the lattice parameters are estiacetic acid. Neither cyanoacetic acid or cyanacet- mated uncertainties in the graphical extrapolation. amide produced any of the symptoms of BAPN The solid solution has the fluorite structure, the toxicity when fed to weanling rats a t the rate of 2 same as PuOz and UOz. mg. per ml. of drinking water for seven weeks.' TABLE I Cyanoacetic acid may be a detoxication product of U02-Pu02 SOLID SOLUTION FLUORITE STRUCTURE BAPN. Its relationship, if any, to the connective Compn. (mole % PuOz) Lattice parameter (A,, 25') tissue degeneration characteristic of BAPN toxicity 0 5.4700 zk 0.0001 is not known. 12 6 f 0.3
(5) D. E. Green, B i d . Reus., 29, 330 (1954).
(6) J. L. Wood and S. L. Cooley, J. B i d . Chem., 118, 449 (1056) (7) J. J. Lalich, unpublished experiments.
DEPARTMENTS OF BIOCHEMISTRY AND PATHOLOGY UNIVERSITY OF WISCONSIN MADISON, WISCONSIN RECEIVED MARCH 6, 1958
S. H. LIPTON J. J. LALICH F. M. STRONG
UOt-Pu02 SOLID SOLUTIONS*
Sir: An X-ray diffraction investigation has been made of the solid phase relationships in the UO2-PuO2 system. The results show that a continuous solid solution exists, and that the lattice parameter varies essentially linearly with composition. A slight negative deviation from linearity may exist. Some trouble was experienced in preparing satisfactory samples of the mixed oxide. Plutonia is an extremely inert substance, and a t 1000° the reaction rate between PUOZand UOz is very slow. Various ways of producing an intimate mixture of plutonium and uranium compounds that could be converted to oxide were tried. The method which seemed best was to co-precipitate Pu(0H)d and (NH&UzO, by dropping a Pu(1V)-U(V1) solution (total metal concentration cu. 14 g./l.) into hot ammonium hydroxide, taking care to keep the pH always above 8. The mixed precipitate was dried in air a t 70°, then fired in hydrogen by raising the temperature to 100OO over 6 or 7 hours and holding a t 1000O overnight. Samples were furnace-cooled in hydrogen. It appears to be quite important that the firing be done in such a way as to avoid the production of well crystallized PuOz as a separate phase. For example, a solid solution was not produced by initial firing of the hydroxide precipitate in air followed (1) Work done under the auspices of the Atomic Energy Commisdon.
20.0 f . 3 35.9 f .3 45.1 f .3
63.1 f . 3 73.8 =I= .3 79.4 i .3 100.0
5.449 5.4544 5.441 5.4345 5.420 5.414 5.407 5.3960
f .003 f .0006 f ,003 ,0005 .000 f ,002 f ,003 f .0003 =I= f
Thanks are due the Misses Marian Gibbs and Gladys Sturdy for measuring the films and preparing the samples, respectively; and Mr. A. Zerwekh for the Plutonium assays. UNIVERSITY O F CALIFORNIA ROBERTN. R. MULFORD Los ALAMOSSCIENTIFIC LABORATORY Los ALAMOS,NEW MEXICO F. H. ELLINGER RECEIVED MARCH1, 1958 S-ADENOSYLMETHIONINE AND ERGOSTEROL SYNTHESIS Sir :
The side-chain C-28 methyl group of ergosterol have been shown to arise intact from m e t h i ~ n i n e . ~ . ~ This transfer of a methyl group was of interest since this was the first demonstration that a carbon atom may act as the acceptor of a methyl group. I n order to participate in certain methyl additions, methionine must first react with ATP4 to form an adenosylsulfonium compound, S-adenosylmethionine,bwhich may then act as the methyl donor to the appropriate acceptor. Involvement of S-aclenosylmethionine as the actual donor in the transfer of methyl groups to sulfurs and nitrogen7 has been de(1) This work was performed under the auspices of the U.s. Atomic Energy Commission. (2) G. J. Alexander, A. M. Gold and E. Schwenk, THIS JOURNAL, 79, 2967 (1957).
(3) G. J. Alexander and E. Schwenk, ibid., 79, 4554 (1957). (4) H.Borsook and J. W. Dubnoff,J . B i d . Chem., 171, 863 (1947). (5) G. L. Cantoni, THISJOURNAL, 74, 2942 (1952). (6) S. K. Shapiro, Bacferiol. Proc. A m . Bacleriologisfs, 116 (1957). (7) G. L. Cantoni. Phosphorus Mcfabolirm, 2 , 129 (1952).
